This invention relates to the preparation of oil-soluble, metal-containing compositions and to the use of such compositions in lubricants and fuels. More particularly, this invention relates to the metal overbasing of organic acids by the use of a boron compound.
Conventional overbasing uses acidic gases, such as CO.sub.2, SO.sub.2 and H.sub.2 S with CO.sub.2 being the most preferred inorganic acidic material. This is due to overall considerations of cost, ease of use, availability and performance of the resulting products. This type of overbasing wherein M is a metal occurs in the following manner: An excess amount of a metal hydroxide is reacted with an acid. This acid reacts with a stoichiometric amount of the metal hydroxide to form a metal salt. CO.sub.2 is introduced into the reaction system, and the CO.sub.2 immediately reacts with the metal hydroxide to form a metal carbonate. The presence of the large amount of metal carbonate in the reaction system is evidence of overbasing.
This invention deals with the formation of an overbased product formed by the reaction of zinc oxide, zinc hydroxide, copper oxide or copper hydroxide with an organic acid to form the salt. Additional zinc oxide or copper hydroxide is added along with boric acid to form a zinc or copper borate overbased acid.